Inkjet printing technology creates images by ejecting small ink droplets onto a substrate from multiple nozzles attached to a printing head assembly. Inkjet printing is very versatile and can be used for a wide variety of printing applications. For example, inkjet printing devices are widely used to produce standard sized documents. However, inkjet printing devices are also often used to print images onto large signage items such as billboards and banners.
In this range of different applications, inkjet printers may be used to print images on a wide variety of different substrate materials. The substrate materials may differ in texture and other physical or chemical properties.
In printing items other than standard sized documents, such as signage, the substrate that receives the printing is often not of a white color. Nevertheless, the color accuracy of the printed image may be generally dependent on the whiteness of the surface on which it is printed. Consequently, a white layer may be applied to a substrate before an image is printed using an inkjet system.
However, the pigments used to create white inks are generally not well suited to inkjet printing technologies. For example, titanium dioxide (TiO2) is a common white ink pigment and is generally three to four times heavier than pigments for other color inks. Thus, the higher density pigment typically precipitates and clogs the nozzles of inkjet systems. Consequently, a white layer is typically applied to a non-white substrate using an alternative printing method prior to having the color image applied by an inkjet printer.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.